How to: Renovate a sand bunker

Wallace "Tinker" Clift, Texas State Technical College

Step 6: Consider water movement into the bunker.

Water movement is an important concept to keep in mind when working on
bunker faces. You can avoid surface runoff into bunkers by building a lip 6
to 12 inches high or installing an interceptor drain at the top. This type
of drain intercepts surface water before it reaches the bunker. To install
it, use a 4-inch flexible ABS perforated pipe in a 6-inch-wide trench that
is 16 to 18 inches deep. Fill it with 3/8-inch pea gravel. You then can
connect this pipe to an existing drainage system. Allow the existing turf
to grow over it naturally. Do not lay sod over the ditch.

Step 7: Address edging problems.

Bunker faces are not the only aspects of a bunker that you must address
during renovation. With the advent of mechanized bunker rakes, many courses
have experienced problems arising from their misuse. Specifically, the
mechanized rakes tend to push sand to the outside over the edge. In so
doing, it becomes difficult to tell when you are inside the hazard or
outside of it.

Therefore, you must define and shape the fairway side of the bunker. The
edge should be 4 inches below grade to allow for sand replacement. It is
important that the back and sides are flush with existing ground level.
This facilitates surface drainage and eliminates a vertical lip that can
interfere with a golfer's swing. After all, sand bunkers should offer the
golfer a chance to advance the ball toward the hole.

Step 8: Re-establish bunker edges and banks.

You can use two methods to reinstall a well-defined border, which gives the
bunker its final shape and aesthetic appeal.

Method 1: First identify whether your bunker is on a flat--or relatively
flat--plane. If so, you can use strips of plywood or metal sheeting to
support banks during turf re-establishment. Obviously, this method works
best where your bunker needs little support.

Method 2: For bunkers with large elevated capes and mounds, follow these
steps:

Fill burlap bags about three-quarters full with topsoil.

Lay the burlap bags out to establish your edge.

Fill between the bags with soil.

Place sod on top of the bags, laying the sod over the rounded edges of the
bags.

Perform final edging after the grass has grown and the bags have decomposed.

You can mold and move the burlap sacks to provide the precise, desired
effect of the bunker. In time, the burlap deteriorates. In the interim, it
does an excellent job of protecting the bunker from soil washing into the
bunker.

Step 9: Install appropriate drainage.

Good drainage is essential for all areas of the golf course. Sand bunkers
are no exception. Good drainage, in fact, is probably the most important
step in bunker renovation. After all, a bunker that allows sand to wash
from its faces is a bunker with a short sand life due to contamination.

If necessary, install a smile drain (4-inch ABS perforated pipe) at the top
of the slope to intercept runoff.

Step 10: Install the sand.

The USGA established bunker-sand guidelines in 1974. These guidelines
recommend sand particles between 0.25 and 1 millimeter that are angular in
shape. (This is the same recommendation for greens construction.)

Before buying replacement sand, send a 1-gallon container of each type of
sand you are considering for use to a soil-testing lab. The USGA bases its
guidelines on laboratory tests, practical work and experience. Therefore,
it's important that you evaluate the sizes, shape, purity, color and
composition of the sand you may use. After all, a sand's particle size
significantly determines its playability. And having the correct particle
size in a green-side bunker prevents larger particles from sitting up on
the turf surface and interfering with ball roll and damaging greens mowers.

You also must check each load of sand to make sure it is uniform and of the
same type you originally selected. Make sure trucks were clean before sand
was added and no foreign material was left in them.

With increasing costs and budget restraints, any labor-saving procedure you
can find is beneficial. And renovating your bunkers using the preceding
guidelines can help lessen future maintenance needs.

Stabilize soil to discourage contamination
Stabilizing soil on the face and bottom of sand bunkers can help prevent
sand contamination. Several products are currently available with various
coatings. Whether they are economical and perform the job for which you
need them varies from one site to another.

Several types of woven fabric also are available that help form a barrier
between soil and sand. Unfortunately, the failure of these units due to the
misuse of mechanized bunker rakes is common. Therefore, these fabrics have
been unpopular with some superintendents.

Another option is a new material of synthetic polymer and limestone
screenings. You blow the material into place, much like Gunite is sprayed
onto swimming-pool walls. Upon curing, the material becomes a dense
undercoating, capable of resisting environmental extremes. Although the
product's longevity is not yet proven, it looks promising.